Rear bumper for an automobile



FIG. 1 is a perspective view of a rear bumper for an automobile, showing our new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a top plan view thereof; and,

FIG. 4 is a right side elevation view thereof.

The broken lines in the drawings illustrate portions of the rear bumper for an automobile that are environmental and form no part of the claimed design. 

CLAIM The ornamental design for a rear bumper for an automobile, as shown and described. 